Analyzes the androgenic and estrogenic effects of testosterone (T) in stimula-ting growth and the production of growth hormone (GH) and IGF1 at puberty. Boys with delayed puberty will be treated either with T or dihydrotestosterone (DHT). Those effects seen with T treatment but not with DHT are attributable to estradiol, whereas the effects of DHT are considered purely androgenic. Para-meters to be followed include height velocity, bone age, spontaneous and stimulated plasma GH, and IGF1.